My Presario 12XL405A Celeron 700MHz now has a problem for booting up (POST, PowerOnSelfTest) The symptom in the beginning is the booting process (POST) intermittently success. Sometimes if the POST fails, I do power off and power on again and it will success with the POST, but now TOTALLY won't boot-up. If I turn this unit on by pressing the power button, the PowerLED lit on but there is no indication of booting up, only the HDD produce a clicking sound for a while then silent. I remember in the past the HDD will produce another spinning sound when it successfully boot-up. I have changed to another new HDD but the same result, only a clicking sound and no spinning sound. There is nothing on the screen, formerly when this unit works normally... the screen will show a COMPAQ logo. I still able to turn off the unit by pressing the power button for awhile. I did dismantle the unit and checked for the power section. This power section is controlled by a Maxim IC. I have measured the voltage around some capacitors and coils and can find 5Volt, 3.3Volt. The fan still spins whenever the processor start to get warm. I find 2 VIA chips and both are warm, this is an indication that these two chips are probably working well. The four memory chips which build up 64MB on-board memory do not produce any heat at all. I have tried to take out the processor and test the Celeron processor on desktop and it works perfectly. Searching on the net I found h**p://[URL="http://www.badcaps.net"]www.badcaps.net[/URL] and information about the bad capacitors. I follow the instruction and change all the electrolyte caps and still no result. I also suggested by Victor the boss from allservice forum h**p://[URL="http://www.allservice.ro/forum/viewtopic.php?t=303"]www.allservice.ro/forum/viewtopic.php?t=303[/URL] to re-ball the IDE controller or DMA. I think his suggestion is to re-ball the VIA chipsets which is very difficult for me to do this, but I will try to find solutions for this re-ball. Any one can help me or give me more clues or ideas regarding this case??? Or any other sites / forums where I can find more information ?? If this Presario success, I think my other Acer Travelmate 291Xci can be cured also using the same medicine. ;-) hopefully. All comments and response appreciated. Thanks. Fabianus